Focused Seismic Monitoring (FSM) on Snorre

Transcription

1 Classification: Statoil Internal Status: Draft Focused Seismic Monitoring (FSM) on Snorre The fourteenth SPE Bergen One Day seminar 18th April 2007 Mona Andersen

2 2 Outline Introduction to the Snorre Field 4D history on Snorre The FSM project Further 4D plans FSM analysis Lessons learned

3 3 Base Cretaceous Map - Tampen Large field: 25 x 8 x 1 km Snorre Large STOOIP: ca. 500 MSm 3 Statfjord North Statfjord East Statfjord Vigdis Borg Tordis A Visund Gullfaks N

4 Cross section across the Snorre Field 4 Snorre TLP Nordland Gp. Triassic and lower Jurassic Utsira Fm. fluvial deposits Hordaland Gp. Balder Fm. Sele/ Lista Fm. Shetland Gp. Cromer Knoll Dunlin Gp. P-21 P-33 P-34 P-40 P-19 P-35 WFB CFB EFB Snorre UPA 5 reservoir models, which includes: Several pressure barriers 9 fault blocks with several initial OWC per block A-9HT2 A-5H A-17H ECFB Facts and challenges; Thin reservoirs Thief zones Pressure barriers Complex fault pattern Active use of WAG Smart wells Poor recovery: 45% Large IOR potential!!! RF ambition: 55 % Model driven decision making SnTLP_Res CrossSect ETj

5 5 4D history on Snorre Ongoing 4D analysis on Snorre; 97-06, 01-06, Previous 4D analysis on Snorre; D responses in both Statfjord and Lunde Fm. which are related to production and injection; 4D? Ekke det fali det a? Water and gas fronts Pressure build up around injectors Changes along the OWC

6 6 4D history on Snorre 4D data Production data WAG optimizing Well planning TRO process (Infill) Simulation model Geological model Drainage pattern Well intervention Create values $

7 7 The FSM project Evaluated the need for focused seismic monitoring across the Snorre Field; size frequency type of acquistion based on remaining reserves expected drilling activity expected value of increased understanding of the reservoir and the drainage pattern

8 The FSM project Areas of interest 8 A mature area; expensive wells infill phase planning WAG thief zones A immature area; large uncertainties about communications remaining attic oil due to well design High drilling activity

9 The FSM project Recommendation 9 From Snorre; FSM has large potential at Snorre to optimise drilling targets and to increase the reservoir drainage understanding. The FSM area(s) should cover at least an area of km 2 to be sufficient regarding mapping gas and water front directions. The frequency of acquisition depends on gas and water breakthrough, WAG cycles, well planning. A short turnaround is important.

10 The FSM project Recommendation 10 From R&D; Use permanent fibre optic cables, because; Snorre need high degree of repeatability to do a detailed analyse of small 4D effects and understand the complex drainage pattern. Snorre should adopt a robust system that allows for a minimum turnaround. The risk (instrument) is moved to top-side by using fibre optic cables. HES less crew exposed for risk Statoil concern initiative regarding IOR and integrated operations

11 11 Permanent ocean bottom cables (Fibre optic)

12 12 Further 4D plans FSM pilot on Snorre during 2007 If the pilot is a success => recommend an extension Dedicated 4D team (multi disciplinary) Conventional 4D seismic Ongoing 4D analysis of 2006 data Ongoing 4D analysis of data Planning new surveys for the future

13 FSM on Snorre The objectives 13 ST0505 survey ~ 100 km 2 FSM area Fully migrated ~70 km 2 Undershoot area 1) map 4D effects to use in well planning, TRO, update of simulation model etc.. 2) compare the 4D survey in 2006 to evaluate whether 1 year between vintages give sufficient 4D effects 3) evaluate the size of a FSM area

14 14 FSM on Snorre Workprocesses Work processes Preparation QC of data Visualization Integration Implementation Documentation

15 FSM on Snorre Preparation 15 What are the challenges and the plans for the area??? 9S B C-2HT2 4 7 Drainage pattern? Communication across faults? A-10H UPA

16 FSM on Snorre Visualization 16 Geoanomalies in GeoProbe Snorre 3 ADC data RMS Amplitude attribute Snorre 3 ADC data

17 FSM on Snorre Data integration 17 No 4D effect Strong Sw response Strong 4D effect Weak Sw response From simulation model Sw model From 4D data 4D ADC 97-05

18 18 FSM on Snorre Data implementation in Eclipse

19 FSM on Snorre Data implementation 19 Eclipse history match ex. RFT match Base case simulation model RFT match Edited simulation model RFT match => Better match by using the 4D data!!

20 20 Lessons learned from 4D work A lot of information!! Use well know software applications (SeisWork, GeoProbe and RMS) Need to focus on integration and implementation of 4D data Multi-disciplinary work!! Need more calibration points (repeated logs and PLT) 4D er ikke fali it is motivating, informative and it create values 4D? Ekke det fali det a?